Glucose biosensor based on self-assembled gold nanoparticles and double-layer 2d-network (3-mercaptopropyl)-trimethoxysilane polymer onto gold substrate

A novel glucose biosensor fabricated by self-assembling of double-layer 2d-network of (3-mercaptopropyl)-trimethoxysilane (MPS), gold nanoparticles and glucose oxidase (GOD) has been studied on gold substrate. A clean gold electrode was first immersed in solution of MPS in ethanol to produce a self-assembled monolayer, and then the silane units were polymerized into a 2d-network by dipping into aqueous NaOH. The second silane layer was then formed by immersion back into the MPS solution overnight, and then the gold nanoparticles were chemisorbed onto the thiol groups of the second silane layer. Finally, GODx was adsorbed onto the surface of the gold nanoparticles. The modified process was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Analytical parameters, such as pH and temperature, were also studied. With the aid of Co(byp)33+ as a mediator in the solution, the electrode displayed excellent electrocatalytical response to the glucose. The peak currents were proportional to the glucose concentration in the range of 4.00×10−10 to 5.28×10−8 M with a correlation coefficient of 0.99. Moreover, such a modified electrode exhibits a good stability and sensitivity.